1. Technical Field
This invention is directed toward an air conditioning/dehumidifying unit and a method of operating the unit. The invention is more particularly directed toward an air conditioning/dehumidifying/pool water heating unit for use with indoor swimming pools and to a method for operating the unit.
2. Background Art
Air conditioning/dehumidifying units normally have air passageway means with a main passageway and air inlets and outlets associated with the main passageway. The units have refrigeration means with an evaporator, followed by a first condenser, in the main passageway and a second condenser outside the main passageway and usually outside the building housing the main passageway. Fan means are provided to draw the air to be conditioned/dehumidified through the passageway including through the evaporator and the first condenser in the passageway. The first condenser in the passageway is used to reject heat during dehumidification. The second condenser outside the passageway is used to reject heat during air conditioning.
Having the second condenser outside the passageway, and usually outside the building housing the passageway, on most air conditioning/dehumidifying units, particularly those used for indoor swimming pools, has a number of disadvantages. The location of the second condenser, separated as it is from the remainder of the unit, requires a relatively large amount of refrigerant for proper operation of the unit. The large amount of refrigerant required is quite expensive and to replace any leakage is also expensive. The use of a large amount of refrigerant also requires the use of refrigerant oil adding to the cost. The use of a large amount of refrigerant further requires many controls, including costly control valves, to protect the compressor from liquid flood back. The installation of the control valves, involving brazed joints, is costly. Servicing and/or replacement of the valves is also costly. Also, the shipping and installation of the second condenser is relatively complicated and expensive. Installation requires construction of a separate pad for the second condenser; a separate electrical service; the installation of associated refrigerant piping at the site to connect the condenser to the rest of the unit; the loading of the refrigerant charge into the unit at the site; and the necessary testing required on-site once the unit is installed to ensure that it operates correctly in all modes of operation. In addition, the location of the second condenser outside the building may detract from the appearance of the building.
It is known to have air conditioning/dehumidifying units for indoor swimming pools that heat the pool water. The units have a refrigerant/pool water heat exchanger. Older units used a simple water valve to control the flow of water through the heat exchanger as needed. Hot refrigerant gas was continually passed through the heat exchanger to heat the pool water. When heating of the pool water was not required, the hot gases passing through the heat exchanger caused mineralization of standing pool water in the heat exchanger. As a result, deposits built up in the heat exchanger and slowed the flow of water through it. Cleaning/replacement of the heat exchanger was expensive. Newer units now usually employ at least one diverter valve to divert hot refrigerant gas to the heat exchanger to heat the pool water as required. Diverter valves are however expensive to use and to replace since refrigerant must be removed from, and then added to, the refrigerant system during replacement.